Wireless communications systems have become a ubiquitous feature of modern society. Wireless system performance is affected by various conditions that distort or interfere with the wireless signals. Additive noise, which may be induced by the system components themselves or by external noise sources, is one factor affecting the quality of received signals in a wireless system. Noise variance is a measure of the statistical dispersion of the noise magnitude of a received signal. In communication systems, the receiver processing may require an estimation of the noise variance for a variety of reasons. For example, minimum mean-squared error (“MMSE”) equalization and log-likelihood ratio (“LLR”) computation use the noise variance. Channel estimation may also be improved if the noise variance is known prior to computation of the channel estimate. Accordingly, estimation of the noise variance of a received signal without knowledge of the channel is desirable.